The invention generally relates to power tools and more particularly relates to a miter saw having a pivotable support arm with a detent mechanism to provide pivot stops at certain bevel angles.
Power miter saws are generally known. Typically, a power miter saw includes a base having a fixed support platform having a rip fence and a turntable that is rotatably mounted to the base, a movable arm assembly extending from the turntable, and power saw unit mounted to the arm for cutting a workpiece on the turntable. To make standard miter cuts, the arm holds the saw unit so that its circular blade is generally vertical.
A compound miter saw additionally includes a bevel angle joint that permits the angular adjustment of the arm to hold the blade at a bevel angle, generally between 0-45 degrees from vertical. Detent mechanisms are generally known for locking the bevel angle joint at common angles, for example 0, 33.9 or 45 degrees, however, an improved detent mechanism is desired. Some known detent mechanisms include steps integrated into the structure of the support arm, wherein the bevel angle is limited by contact of one of the steps against detent pin. It is desirable to provide a miter saw having a step-like detent mechanism that permits easy adjustment of the position of one or more of the steps relative to the arm to facilitate fine adjustment of a corresponding pivot stop position.
The invention provides an improved compound miter saw which permits precise adjustment of detent steps that correspond to bevel angle stops. For example, in an embodiment, a compound miter saw is provided which includes: a base; a movable support arm assembly for holding a tool unit, the support arm having a hub portion that is rotatably mounted to the base to permit rotation of the support arm relative to the base along an axis; a detent block having a plurality of generally parallel, planar surfaces adjacent surfaces are positioned at different axial depths relative to each other so that the adjacent surfaces are separated by a respective step; a detent pin carried by the base for movement in a direction generally parallel to the axis and generally perpendicular to the surfaces; and a biasing element urging the detent pin into contact against one of the surfaces; wherein each surface defines a range of possible bevel angle positions of the support arm, and the step can abut the pin to limit a pivoting of the support arm at a corresponding predetermined bevel angle and wherein the detent block is adjustably mounted to the support arm to permit adjustment of the position of the step relative to the support arm. Preferably, each of the steps is planar and radially oriented relative to the axis.
In an embodiment, the hub portion includes a recess shaped to receive the block and to provide space for adjustment of the block either clockwise or counterclockwise relative to a center of the hub. The hub further includes fasteners, such as set screws, to secure the detent block at a desired position.
In an embodiment, the compound miter saw further includes a linkage operable to move the detent pin. With the linkage, a user can retract the detent pin to clear one of the steps, permitting the support arm to move to a bevel angle beyond the pivot stop defined by the respective step. Preferably, the linkage includes a handle is positioned generally at a side of the base which is generally opposite of the hub.
In an embodiment, the detent block is generally arcuate, and wherein the detent block is mounted to the hub generally concentrically to the axis.
In an embodiment, at least one of the steps includes a threaded bevel angle adjustment bolt to adjust the bevel angle at which the step contacts the detent pin.
An advantage of the present invention is that it provides an improved compound miter saw.
Another advantage of the present invention is that it provides a compound miter saw in which a xe2x80x9chomexe2x80x9d bevel angle position, such as a vertical (0xc2x0) position, is precisely adjustable.
A further advantage of the present invention is that it provides a compound miter saw that has few parts and which is simple to assemble in a precise manner.
Yet another advantage of the present invention is that it provides a compound miter saw having a tiltable support arm, wherein pivot stops can be released by a linkage actuatable from a front of a saw. A related advantage is that the miter saw of the invention provides enhanced safety, avoiding a need for a user to reach around or over the saw to move a detent pin located near a rear of the saw.